hw/i386/kvm/clock.c

   1 /*
   2  * QEMU KVM support, paravirtual clock device
   3  *
   4  * Copyright (C) 2011 Siemens AG
   5  *
   6  * Authors:
   7  *  Jan Kiszka        <jan.kiszka@siemens.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL version 2.
  10  * See the COPYING file in the top-level directory.
  11  *
  12  * Contributions after 2012-01-13 are licensed under the terms of the
  13  * GNU GPL, version 2 or (at your option) any later version.
  14  */
  15
  16 #include "qemu-common.h"
  17 #include "sysemu/sysemu.h"
  18 #include "sysemu/kvm.h"
  19 #include "hw/sysbus.h"
  20 #include "hw/kvm/clock.h"
  21
  22 #include <linux/kvm.h>
  23 #include <linux/kvm_para.h>
  24
  25 typedef struct KVMClockState {
  26     SysBusDevice busdev;
  27     uint64_t clock;
  28     bool clock_valid;
  29 } KVMClockState;
  30
  31
  32 static void kvmclock_vm_state_change(void *opaque, int running,
  33                                      RunState state)
  34 {
  35     KVMClockState *s = opaque;
  36     CPUArchState *penv = first_cpu;
  37     int cap_clock_ctrl = kvm_check_extension(kvm_state, KVM_CAP_KVMCLOCK_CTRL);
  38     int ret;
  39
  40     if (running) {
  41         struct kvm_clock_data data;
  42
  43         s->clock_valid = false;
  44
  45         data.clock = s->clock;
  46         data.flags = 0;
  47         ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
  48         if (ret < 0) {
  49             fprintf(stderr, "KVM_SET_CLOCK failed: %s\n", strerror(ret));
  50             abort();
  51         }
  52
  53         if (!cap_clock_ctrl) {
  54             return;
  55         }
  56         for (penv = first_cpu; penv != NULL; penv = penv->next_cpu) {
  57             ret = kvm_vcpu_ioctl(ENV_GET_CPU(penv), KVM_KVMCLOCK_CTRL, 0);
  58             if (ret) {
  59                 if (ret != -EINVAL) {
  60                     fprintf(stderr, "%s: %s\n", __func__, strerror(-ret));
  61                 }
  62                 return;
  63             }
  64         }
  65     } else {
  66         struct kvm_clock_data data;
  67         int ret;
  68
  69         if (s->clock_valid) {
  70             return;
  71         }
  72         ret = kvm_vm_ioctl(kvm_state, KVM_GET_CLOCK, &data);
  73         if (ret < 0) {
  74             fprintf(stderr, "KVM_GET_CLOCK failed: %s\n", strerror(ret));
  75             abort();
  76         }
  77         s->clock = data.clock;
  78
  79         /*
  80          * If the VM is stopped, declare the clock state valid to
  81          * avoid re-reading it on next vmsave (which would return
  82          * a different value). Will be reset when the VM is continued.
  83          */
  84         s->clock_valid = true;
  85     }
  86 }
  87
  88 static int kvmclock_init(SysBusDevice *dev)
  89 {
  90     KVMClockState *s = FROM_SYSBUS(KVMClockState, dev);
  91
  92     qemu_add_vm_change_state_handler(kvmclock_vm_state_change, s);
  93     return 0;
  94 }
  95
  96 static const VMStateDescription kvmclock_vmsd = {
  97     .name = "kvmclock",
  98     .version_id = 1,
  99     .minimum_version_id = 1,
 100     .minimum_version_id_old = 1,
 101     .fields = (VMStateField[]) {
 102         VMSTATE_UINT64(clock, KVMClockState),
 103         VMSTATE_END_OF_LIST()
 104     }
 105 };
 106
 107 static void kvmclock_class_init(ObjectClass *klass, void *data)
 108 {
 109     DeviceClass *dc = DEVICE_CLASS(klass);
 110     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
 111
 112     k->init = kvmclock_init;
 113     dc->no_user = 1;
 114     dc->vmsd = &kvmclock_vmsd;
 115 }
 116
 117 static const TypeInfo kvmclock_info = {
 118     .name          = "kvmclock",
 119     .parent        = TYPE_SYS_BUS_DEVICE,
 120     .instance_size = sizeof(KVMClockState),
 121     .class_init    = kvmclock_class_init,
 122 };
 123
 124 /* Note: Must be called after VCPU initialization. */
 125 void kvmclock_create(void)
 126 {
 127     if (kvm_enabled() &&
 128         first_cpu->features[FEAT_KVM] & ((1ULL << KVM_FEATURE_CLOCKSOURCE) |
 129                                          (1ULL << KVM_FEATURE_CLOCKSOURCE2))) {
 130         sysbus_create_simple("kvmclock", -1, NULL);
 131     }
 132 }
 133
 134 static void kvmclock_register_types(void)
 135 {
 136     type_register_static(&kvmclock_info);
 137 }
 138
 139 type_init(kvmclock_register_types)